Expert Panel Cites Doubts On Mammogram's Worth

By GINA KOLATA

Published: January 24, 2002

ROCKVILLE, Md., Jan. 23—
An independent panel of experts said today that there was insufficient evidence to show that mammograms prevented breast cancer deaths.

The group, which meets regularly to assess evidence on cancer and provide that information to doctors and to the public, said that while it was possible that mammograms were beneficial, it was also possible that they were not.

The group, called the P.D.Q. screening and prevention editorial board, agreed here today that seven large studies of mammography had serious flaws, weakening or casting doubt on the studies' validity.

The group, which writes information for the National Cancer Institute's online database, said that it would rewrite previous statements to reflect its new view.

Previously, the group, which does not make specific recommendations for medical practices, had said that the evidence showed that mammograms prevented breast cancer deaths starting at age 40.

The decision by this group clouds a continuing debate over whether women should have regular mammograms. Since 1997, the National Cancer Institute has also recommended that women have regular mammograms, starting in their 40's.

For now, the cancer institute, whose new director, Dr. Andrew C. von Eschenbach, was sworn in on Tuesday, has not announced any plans to revisit the issue, raising the question of whether the institute will end up with conflicting information on its Web site, with one statement saying that the screening is beneficial and another saying that those benefits have not been proved.

The institute's Web site, www.cancer.gov, says that women in their 40's and older should have the test and that it reduces the breast cancer death rate by as much as 30 percent.

Members of the P.D.Q. board said they knew that it was not going to be easy for women and doctors to decide what to do. At the meeting, the members wrestled with the question of how much benefit, if any, mammograms confer. Some, like the board chairman, Donald A. Berry, chairman of the department of biostatistics at M. D. Anderson Cancer Center in Houston, said they thought it was unlikely that there were benefits that could make the test worthwhile.

But others said that they were uncertain and that they were having a hard time coming to terms with the profound flaws they now saw in studies they had thought put mammograms on solid ground.

''What this new material has contributed is a softening, at least in my mind, of what I thought was true,'' said Dr. Isra Levy of the Canadian Medical Association. ''I still think that for women aged 50 to 69 there might be something there. But we've had our confidence shaken.''

In the end, the group decided not to deal with age, saying doubts persisted for women of all ages.

The group focused on flaws in the studies that were recently uncovered by two scientists in Denmark. The report, published in October by Dr. Peter C. Gotzsche and Ole Olsen of the Nordic Cochrane Center in Copenhagen, concluded that the case for the screening was unproven. The studies were so poorly designed and carried out that they might have found benefits when there were none or exaggerated what benefits there were, the researchers said. None of the studies found that mammography prolonged life, and even when the studies were analyzed as a group, women who had the test lived no longer, dying of diseases other than breast cancer.

Some experts have taken issue with Dr. Gotzsche and Mr. Olsen's analysis. But today, the P.D.Q. board said it believed that the scientists had found serious problems. The board's assessment of mammography is expected to be posted on the cancer institute's Web site in April.

The P.D.Q. board said it would like to see others take on a detailed and independent analysis of the mammography studies and that some of the data that might settle questions about the quality of the studies could be obtained with difficulty.

Some may be in medical records of women in a United States study decades ago. Others are held by Swedish scientists who, the board and others said, have refused to divulge them.

The issue of whether women should have mammograms has been controversial for some time. In January 1997, when an independent panel convened by the National Institutes of Health took on the question of mammograms for women in their 40's, Congress got involved. That panel said then that there was no evidence that the test prevented breast cancer deaths in women under 50 and suggested that those women discuss mammograms with their doctors before deciding to have one.

Before the week was over, the panel's chairman, Dr. Leon Gordis of the Johns Hopkins University, had been summoned by Senator Arlen Specter to testify before Congress. Later, going against the conclusions of the panel convened at its behest, the cancer institute said women in their 40's should have mammograms.

The P.D.Q. board, which issues its statements independently, has also said over the last several years that mammograms prevent breast cancer deaths for women in their 40's.

Today, the P.D.Q. board emphasized that mammograms have drawbacks, leading at times to excessive treatments for tumors that would not have threatened a woman's life.

The group agreed that doctors should respect a woman's decision, adding that it was rational to decide to have mammograms and that it was rational to decide not to.

Whatever they decided, Dr. Berry said in a telephone interview on Tuesday that he was acutely aware of the difficulty in questioning an enormous mammography business.

''Screening programs bring in patients,'' Dr. Berry said. ''It isn't just the mammography, but it's the biopsies, the surgeries and the like. We know that screening is exquisitely fine at finding cancers. Therefore it brings in patients and they demand treatment.''

The problem, he said, is if the women who have mammograms fare no better, or do even worse because of excessive treatment, than women who are not screened.